This invention relates to a system and process for applying or delivering liquid fire retardant material to cotton batts, cotton insulation and the like during course of the production.
The production of cotton batts is an old and well known process using machinery which in general has long been in the public domain. At least several hundred companies throughout the United States produce cotton batts for use in making furniture or mattresses, or for insulation, or for other purposes. For the most part, the basic processes are essentially the same, as described below, although some installations may vary such as to the nature and type of equipment for dust abatement, or conveyors etc. The basic production machinery includes a picker which receives chunks or slabs of compressed raw cotton manually pulled from the bale and put on a feed table feeding the picker. The picker includes a large roller having a number of long spikes which tear the slabs of cotton into smaller pieces. A fine mist of light oil is typically added at this point. These pieces are then transferred to a large housing or hopper containing a conveyor which includes smaller spikes and which further blends and fluffs up the cotton. From this hopper/conveyor called a willow, the cotton is sent to a garnetting machine which includes a significant number of rollers having external spikes and which break the cotton down into finer segments and segregate it into two thin wide webs which are delivered from the last rolls in the garnetting machine called comber rolls. These webs which may be as thin as 1/16 to 1/2 inch are then combined by being conveyed together to provide a double thickness and this double thick layer is then supplied to a lapper conveyor which doubles the layers back and forth, thereby stacking the layers to form a web of the desired thickness. This web is then run through a feed conveyor to a roller to compress the batts as desired before they are cut to desired lengths.
Such cotton batts are, of course, very flammable and there are various requirements that they be treated with some form of fire retardant material. For many years the standard method of making the cotton batts fire retardant has been to apply a fine spray of very light oil to the cotton, usually at the picker. Boric acid powder is then shaken on the cotton web, usually upstream of the lapper conveyor. The fine oil serves both as a dust abatement measure and as a means to cause the boric acid powder to stick to the cotton. This process, although effective, leaves much to be desired because of the need to supply substantial quantities of the oil and boric acid powder; because the boric acid powder tends to create a dust problem despite the use of the oil; and because the boric acid powder is somewhat hazardous to the workers nearby, both because of adverse effects from breathing it and because it becomes very slippery underfoot. It has also been found that the boric acid powder tends to shake out of the cotton batt material after an extended period of time.
Applicants have been aware of the availability of fire retardant materials in liquid form which have been usefully employed in a number of applications where porous or cellulose-type materials are involved. In particular, it has been found to be useful for retarding the spreading of fire in natural fiber materials such as straw, paper and various forms of wood such as plywood, wood shakes or framing lumber. One such liquid fire retardant material is marketed by Nochar, 8101 Crawfordville Road, Indianapolis, Ind. 46253. This material is non-toxic and biodegradable, absorbs into the fibers of the above listed natural fiber materials and does not dry out or separate from the protected material.
In contacting several cotton batting manufacturers, applicants were made aware of the process and equipment described above and the several disadvantages inherent in the application of boric acid powder to the cotton. Testing by applicants of the liquid fire retardant material on the cotton batting demonstrated that the retardant material was effective to reduce the flammability of the cotton material to the level required by the State of California Department of Consumer Affairs Technical Bulletins Nos. 116 and 117. One test specified by this document, which must be complied with to sell cotton batting in furniture or mattresses in California, is that a lighted cigarette placed on the cotton batting material, must not burn or char the cotton more than an inch around the cigarette in any direction. Applicants found that there was no known system for applying a liquid fire retardant material such as that described above to the cotton batting material.